Kirby Lee-USA TODAY Sports. Pictured: Los Angeles Chargers fans pose with a cutout of the head of quarterback Philip Rivers

Nearly 70% of spread tickets are on the Los Angeles Chargers as 2.5-point underdogs against the Baltimore Ravens (1:05 p.m. ET, CBS).

Using Bet Labs, we analyzed how popular underdogs have performed against the spread in the NFL playoffs.

The most popular bet of Wild Card Weekend is not the Chicago Bears, who are the biggest favorites on the slate. It’s not the Cowboys, nor is it the Colts, who are streaking into the playoffs having won four in a row and nine of their past 10 games.

Rather, the Chargers, as 2.5-point underdogs on Sunday against the Ravens (1:05 p.m. ET, CBS), are receiving the most lopsided action. Nearly 70% of spread tickets are behind the Bolts.

Casual bettors loving a pooch? That may not feel right, but it shouldn’t be unexpected in the postseason.

According to the Bet Labs database, NFL favorites have received a majority of bets in 3,206 of 4,086 (78.5%) regular season games since 2003. In the playoffs, however, the chalk isn’t as chalky.

Over that same span, postseason favorites have received at least 51% of spread tickets in only 96 of 164 (58.5%) games.

Why the difference? Many recreational gamblers believe that a team must be talented and well coached to make the postseason. If that’s the case, then it reasons to expect a competitive game and take the points.

Since squares are more willing to bet on underdogs in the playoffs, one contrarian approach would be to back favorites getting little public support (45% or less of bets). While the strategy seems sound, and has been profitable in every other major sport’s postseason, that hasn’t been the case in the NFL.

In the five other major sports, betting against popular dogs in the playoffs has combined to go 401-306-16 (56.7%) on the moneyline and spread since 2003. A $100 bettor would be up $5,274 following this approach.

In the NFL, however, playoff underdogs receiving 55% or more spread bets have gone 27-17-1 against the spread since 2003.

As an outlier to the overall strategy, is the NFL trend one bettors can trust?

It’s difficult to think of a reason why popular underdogs would perform better in the NFL playoffs than other sports. One obvious difference, though, is the sample size of games.

There are only 45 games in our NFL sample, which pales in comparison to the 295 games in the NBA, for example. That makes it possible that regression could come with more game matches, and make it eventually profitable to fade trendy underdogs in the NFL postseason.

So while the Chargers’ spot as popular underdogs has been historically profitable, it would be foolish to wager on LA based on one trend with a small sample of games.

That’s not to say that there aren’t other reasons to like the Chargers, though.

Our Action Network NFL Power Rankings have this game set at LA +1.5, a point lower than the +2.5 currently being offered across the market.